This invention relates to a method of diagnosing lung disorders, particularly epithelial lung tumors. It is known that these tumors produce bioactive substances particularly hormones. It has been the goal of workers to use radiolabelled antibodies to such substances to permit detection of tumors.
One such substance is the hormone calcitonin. According to this invention, antibodies to calcitonin are prepared and labelled with technetium 99 m. These radiolabelled antibodies are prepared as an aerosol which is ventilated by a subject. The particle size is controlled to permit maximum deposition by sedimentation, rather than impaction. The antibodies are localised by immunoreactivity in proximity to the tumor site. Mucociliary clearance removes unbound radiolabelled antibodies. The subject is then subjected to a radio detection means which locates concentration of labelled antibody indicating areas of abnormal hormone production, or tumor sites.